Wireless for the Warrior - Volume 4 Supplement Chap. 267 - 1 The German spy set SE88/5 in a box. A research-story after eight decades. By Thomas Höppe, DJ5RE. Editorial revision by Giselle Jakobs. Spy radios from the „Abwehr“, the German S 88/5: A small transmitter, crystal control- To save space, the coils in the input filter of military secret service in WW2, are num- led with KL2 tube. No receiver, the agents the RF amp and in the detector stage were bered by the following system: a transmitter were sending their messages „blind“ with no wound on Siemens powdered iron cores is marked with an „S“ (Sender), while a ability to receive a response. with cross-shaped shields and an adjustable receiver is marked with an „E“ (Empfänger). core. The abbreviation „SE“ indicates the pres- ence of both a transmitter and a receiver. The SE 88/5: A transmitter and receiver housed first number is a sequential or serial number in separate boxes. The transmitter is the S which simply indicates the period during 88/5 described above, combined with the which the set was developed in the Abwehr receiver „E 88“. This receiver was built workshops. The older the set, the smaller the using the box and mechanical layout of the number. The early sets (1939 and earlier) German standard receiver „E 75“. This re- begin in the 70’s series and the later wartime ceiver was named E 85 in the set SE 85/14 sets used the 100’s series. The last number, and E 90 in set SE 90/40. The design again after the „/“, represents the power of the used three tubes in total for preamp, detector transmitter, but should not be taken too seri- Transmitter S 88/5 with accessories. and AF-amplifier (1-V-1), usually with 3x ously. For some transmitters the number CF7 tubes if usage with a mains power sup- reflects the RF output power, while for oth- SE 92/3: A transmitter/receiver housed in ply was planned. The E 88 was the only ers, the number reflects the DC input power one box. The transmitter used the same sche- known „E 75“ type receiver version modi- on the anode, as they could rarely reach the matic (with KL2 tube) as the S 88/5. The fied for use with 3x KF4 battery tubes. It was indicated value. receiver was a regenerative design with pretty much the same design as that used in During World War II, Germany made plans tuned preamp, tuned detector stage followed the SE 92/3, except with coils on 35mm to invade Great Britain. The codename for by an AF amplifier stage (German: 1-V-1 ceramic form and the possibility of a volume this plan was „Operation Sea Lion“. In prep- audion), each stage using a KF4 battery control via potentiometer at the grid of the aration for a possible invasion, the Abwehr pentode. AF stage, a detail we do not find in the SE tried to establish spies in Britain. This at- 92/3 (Photo of this set on top of this page). tempt was anything but successful and has been a frequent topic of discussion in vari- Abwehr set SE 88/5 ous historical analyses resulting in some- There are several publications which sup- what strange explanations for its failure. We posedly show the SE 88/5 set housed in an will not discuss that here. The first missions unusual transport box. Most radio sets that in 1940 and 1941 were codenamed „Lena“, included a receiver (not just a transmitter) the landings in southern England codenamed were housed in small suitcases made of „Lobster South“ and the landings in Scot- leather or resin reinforced cardboard. The land codenamed „Lobster North“. All of the transport „box“ with hinged lid, the „mouse agents were poorly trained in espionage and key“ TKP and the „Steeg & Reuter“ crystal were caught almost immediately. We will will help us to identify this very rare SE 88/5 not go into the details of those missions. We set. All wartime pictures of the SE 88/5 will instead take a look at the radio sets that seem to be taken of the same set. the spies brought with them, all of which In the mid-1970s, the theme of issue 11 of were powered by dry batteries, working in- „After the Battle“ (ATB) magazine was dependently from the mains supply. Complete SE 92/3 in a suitcase. „German spies in Great Britain“, including © This WftW Volume 4 Supplement is a download from www.wftw.nl. It may be freely copied and distributed, but only in the current form. Page 1 of 6. WftW Volume 4 Supplement, Chapter 267. ver 1.00. Dec. 2020. Wireless for the Warrior - Volume 4 Supplement Chap. 267 - 2 spies from both WW1 and WW2. Within the one can easily recognize that they actually pling, allowing a very compact arrangement pages of the magazine, we find a picture of show the receiver of the SE 92/3 not the SE of the components in the E 92 receiver. our research-target, the SE 88/5 in a transport 88/5. Let’s take a closer look at the details of box: ATB noted that this set belonged to the the schematics at page 4. Volume control. „Lobster North“ team of Drücke and The design of E 88 and E 92 are virtually Another difference between the two receiv- Schalburg.This team had arrived from Nor- identical. Both are regenerative receivers ers (E 88 and E 92) was the option for adjust- way, having crossed the North Sea in a Hein- with tuned preamp, detector stage followed able output volume. The E 88 had three kel HE111. The seaplane found calm seas by one audio stage. The German designation knobs: the large one for frequency control, near Banffshire in North Scotland and the would be ‘1-V-1 Audion’. Both receivers use another for regeneration control (left hand- team reached the coast via an inflatable din- the German KF4 battery tubes. So where do knob), and a third for volume control (right ghy. Drücke and Schalburg came ashore to- the differences lie? The E 88 has standard hand knob) which also included the on/off gether with another agent named Werner 35mm ceramic coil forms, widely known as control. The E 92, on the other hand, had no Wälti. After arriving on the coast, the two ‘Hirschmann Spulenkörper’, although they volume control. The on/off control was a groups separated. Drücke and Schalburg were produced by several companies. They separate switch and the volume control po- went to the railway station in Portgordon, were available with 4 or 5 prong sockets and tentiometer was missing. where their wet clothes and strange accent were intended to be used to realize changea- All of the other schematics, besides those of aroused the suspicions of the stationmaster ble plug-in band coils. Harry Matthews, show no potentiometer at and the pair were quickly arrested. They told The E 88 used only the ceramic body without the grid of the final tube. Even the schemat- the police about Wälti who had caught a train connector pins. The antenna coil and the ics made by the RSS (Radio Security Serv- to Edinburgh from the village of Buckie. The resonance coil of the input stage were wound ice) for MI5 during the war, and which are of Edinburgh police were alerted to Wälti’s on a common coil form, while the coupling the E 88, show no adjustable volume control. presence and, after enquiring at the left lug- coil from the front end, the resonance coil of It would appear that, since the RSS already gage office at the railway station, found a the detector and the tickler coil shared the had the E 92 schematic available to them, suspicious suitcase with salt marks (from second 35mm coil form. These ceramic coil that they simply used that schematic instead seawater) on it. When Wälti returned to re- forms were rather large, wound with single of drawing a new one for the E 88. This trieve his suitcase, he was arrested by Wil- drawing was simply copied again and liam Merrilees, a police officer camouflaged again…until Matthews came along and re- as a railway porter. ATB magazine reports vealed the truth! Veritas vincit! Thank you that Wälti’s radio set was an SE 92/3, while Harry Matthews… good job! Drücke and Schalburg were equipped with But let us return to the question: which agent an SE 88/5 in a transport box. brought the SE 88/5 in the transport box to After the war, it appears that various muse- England? ums were able to acquire former spy radios from MI5. For example, some papers in the National Archives (Kew) document the transfer of various spy artifacts to the Impe- rial War Museum. The Edinburgh police officer, William Merrilees, a very famous person, also seems to have acquired some spy artifacts after the war, including one of the spy radios. Some of these items were later transferred to the police museum in Edinburgh, possibly after Merrilees passed away. Hirschmann ceramic coil (left) When the radio(s?) arrived at the police mu- A few years ago I got two very interesting Siemens powdered iron core coil seum in the 1980s, the boxes were opened by pictures from Paul Reuvers from the Cryp- (right). Harry Matthews, a well-known individual tomuseum. The picture show a showcase and respected specialist in old radio equip- from a museum in Edinburgh and the de- ment who had formerly been employed by layer close wound windings, an arrangement scription.